Although usable on any network, the present invention and the problem underlying it are explained with reference to a network located in a motor vehicle, e.g. the real-time-capable "Controller Area Network" (CAN) serial bus system.
It is commonly necessary to equip network components that are connected via a bus with unequivocal addresses so that messages can be exchanged in directed manner, with an unequivocal allocation, between them. In the present case "addresses" will hereinafter be understood to mean not only addresses of logical point-to-point connections, but also identifiers of object-oriented systems, for example of the CAN system.
These addresses can be permanently allocated to respective network components. For example, the address 00.sub.hex could be permanently allocated to an operating element for an information transfer system in the motor vehicle, and the address 08.sub.hex to a CD changer.
With this permanent address allocation, however, if two identical network components (two CD changers, in the example selected) are operated in the same network, they cannot be individually addressed, i.e. they cannot be individually called up by the operating element (e.g. the car radio), and thus also cannot be distinguished.
The general problem underlying the present invention is thus to make such identical network components individually addressable.
At present, the existing art contains three fundamental approaches to solving this problem.
The first approach provides a programming capability in the network components in order to code them. A software setup accordingly takes place separately in each corresponding network component. This approach is very labor intensive, however, since it requires that each corresponding network component have an input device and an output device to allow the software setup to be performed by a user. An input/output device of this kind can be comparable to a personal computer (PC) or can have an interface therewith.
The second approach provides a hardware wiring capability in the network components in order to code them, i.e., for example, DIP switches or jumpers. This method is also known from measurement and control technology. Here again, an action on the part of the user to set the individual addresses is necessary.
Finally, the third approach provides for assigning an address that is unique (in some circumstances worldwide), consisting for example of a manufacturer name, a product name, and a serial number. Unique addresses of this kind are possible when using assemblies with apportioned and sequential serial numbers (cf., Ethernet). For components having an EEPROM, a unique address can, for example, be assigned during production. Unique codes of this kind allows to assign the particular address or identifier dynamically.
The fact that the above described approaches require a high outlay of cost and operation has proven to be disadvantageous.